Age-Specific Seroprevalence of Anti-Hepatitis A Antibody Among 1-30 Years Old Population of Savadkuh, Mazandaran, Iran With Literature Review

BACKGROUND: To determine age-specific seroprevalence rates of hepatitis A virus (HAV) immunoglobulin G (IgG) antibody in Savadkuh district, Mazandaran province, north of Iran, as well as to compare the collected data with earlier seroprevalence studies in the region and Iran in order to draw a proper epidemiological pattern for HAV infection in the country. OBJECTIVES: This study aimed to assess an age-specific HAV seroprevalence among 1- to 30-yearold people in Savadkuh, a less developed district of Mazandaran province, north of Iran. PATIENTS AND METHODS: The study participants were 984 subjects who aged from one to 30 years and were residents of rural and urban areas of Savadkuh. They were selected using cluster sampling method and divided into five age groups: 1-2.9 (316 cases), 3-6.9 (254 cases), 7-10.9 (201 cases), 11-17.9 (115 cases), and 18-30 (98 cases). Anti-HAV antibody was measured by ELISA method. Seroprevalence rates among different age groups and their relationship to residency, educational levels of parents, water supply, and waste water disposal system was analyzed using chi-squared test. RESULTS: Overall seroprevalence rate was 19.20 % with no significant difference between rural and urban residents. The seroprevalence rates increased significantly with age: from 5.7 % in age group 1-2.9 year to 34.8 % in adolescents, and to 68.4 % among young adults (P < 0.0001); regardless of significant differences in educational levels among parents of residents in two areas it did not affect seroprevalence rates. Findings of this study and reviewing other reports from the region and the country suggest an epidemiological shift towards lower rates of anti-HAV antibody seroprevalence. CONCLUSIONS: It appears that anti-HAV antibody seroprevalence rate has been declining among Iranians and thereby more children would be susceptible to this infection. This would necessitate revising current strategies of preventative measures in Mazandaran and Iran.